Air guns - Pyramyd Air Report

S&W 586 & 686 pellet guns - Part 1

noreply@blogger.com (B.B. Pelletier) — Tue, 06 Jan 2009 11:30:00 +0000

by B.B. Pelletier

Smith & Wesson 586 is a beautiful air pistol.

Wayne asked for this report on the S&W 586, though I think you will see (from the comments we're bound to receive) that a lot of readers either already own this gun or have seriously thought about it. When it was first rumored (early 1998) that Umarex was creating this revolver, I was excited because I'd tested their earlier pistols and found them excellent. If they put the same thought and care into the 586 platform, the results had to be good!

As good as their word!
In November 1998, a friend who worked at Smith & Wesson brought me an advance production model of the black-finished 586 with 6" barrel, and I saw that Umarex had outdone themselves. This was their finest replica CO2 handgun ever--a position it retains to this day, in my opinion.

Very close to the firearm it copies
Let's start our analysis with the prototype S&W 586 revolver in .357 caliber. I'll lump together the 686 and the 586 because the two are identical except for the steel they're made of (the 686 is stainless). The 586 has S&W's L-sized frame (medium-sized) with the K-sized grip (small). That makes a rugged magnum revolver that's easier for most shooters to hold. By swapping grip panels, they can size the gun to personal tastes over a broad range of hand sizes.

IN MY OPINION, the 586 is second only to a Colt Python as the finest .357 double-action revolver in the world. I won't get into all the rationale behind that opinion, but I've thought about things like the smaller and more compact Model 19 which is even easier to handle but is not as rugged with full-house .357 ammo. Your opinion may differ, of course. But regardless of who you are, everyone who enjoys a modern double-action revolver thinks pretty highly of the S&W 586.

Two signature features of the 586 firearm revolver are a smooth double-action trigger-pull and a super-crisp single-action pull. Only the Colt Python is better, and not by that much. I was delighted to discover that the 586 airgun had an even better double-action trigger-pull than the .357, and a single-action pull with only a trifle of creep. Among non-10-meter air pistols, it has few equals, although the Crosman Mark I and II pistols might be two.

I have owned at least one 686 firearm, and possibly more that I can't remember. Being stainless, the 686 revolver didn't interest me as much as a 586 would have, and I parted with it some years ago. But not before verifying that it shot as well as any S&W .357, which is to say very good, indeed.

I bought one of the first 6" 586 pellet pistols to be sold by S&W. The starting MSRP price was high--about $230 in 1998. The street price was more relaxed, at about $190. That initial price pitted the revolver against the Walther CP88, the Colt M1911A1 and the SIG CP225 (which were also made by Umarex and each selling for much less). I believe that slowed the initial acceptance, and the gun never recovered.

Realistic cylinders
The revolver is a 10-shot true revolver with a swing-out cylinder/clip that comes off the crane for loading. The .177 pellets are much smaller than .357 rounds, so more care must be taken to load them right. Although the cylinder swings out to the side on a real crane, it isn't as long as a firearm cylinder and some people object to that. They do so without thinking it through. If the cylinder were full-sized, it would weigh more than a pound, giving them something else to object to. Colt discovered that in the late 1800s when they converted their Single Action Army revolver into a .22 rimfire. Even though the thin cylinder looks odd, there's a real reason it's so thin and it does make sense.

Ten-shot clips slip off the cylinder crane for loading.

Grippy grips
You get something with this pellet gun that even S&W doesn't offer--a pair of molded rubber grips. Smith & Wesson wood grip panels don't fit every hand, like mine for instance, so many shooters replace them with rubberized grips from companies like Hogue. This pellet pistol comes that way from the factory. Since I'm used to Hogue grips, I view this as a bonus. The drawback is that there are no aftermarket grips available, as far as I know.

This is a CO2 revolver, and the cartridge resides inside the grip, of course. The right panel pops off to expose the place where the cartridge lies, and Umarex designed a lever mechanism at the bottom of the frame to push the cartridge up for piercing. They knew appearances were important with this pistol and it would not do to have an ugly winding key exposed under the grip.

Right grip pops off for access to the CO2 cartridge. The complex hardware inside the molded rubber grip is the reason aftermarket grips are not available.

Barrel swaps
Another wonderful feature of this revolver is not based on Smith & Wesson revolvers but on those of Dan Wesson. It has interchangeable barrels! Owners can change to 2.5", 4", 6" and 8" barrels at will. During the glory days of the gun, Umarex sold a pistol pac, not unlike the ones from Dan Wesson. In that set you got a single frame with the 4", 6" and 8" barrels and shrouds. Those are collectible sets now, and the gun usually sells as a fixed-length barrel, only. You can still buy spare barrels and shrouds of different lengths, and a plastic wrench that comes with every gun lets you make the switch.

Size and weight were close
The specifications of the pellet pistol were remarkably similar to the firearm. My unloaded 6" 686 weighed 45.8 oz., and the 586 pellet pistol weighs 46.5 oz. with a CO2 cartridge installed (but no pellets in the cylinder). The length, width and height are all within hundredths of an inch of those on the firearm. A Smith & Wesson owner will feel comfortable with this gun, which has no plastic on the outside.

I no longer own the pellet pistol, so this report is based on tests I did and photos I took when I had it, plus S&W sent a couple pistols with different barrel lengths for me to sample. I tell you that now so you will understand why I cannot expand my report beyond what I'm giving you. Next time, I'll finish with the velocity and accuracy.

.177 Gamo Big Cat - Part 1

noreply@blogger.com (B.B. Pelletier) — Mon, 05 Jan 2009 11:30:00 +0000

by B.B. Pelletier

Gamo Big Cat is an impressive breakbarrel for an impressive price!

Certain readers have been after me to review the Gamo Big Cat for close to a year, and today I'll start! I'm already impressed by the current crop of Gamo rifles, as evidenced by my 8-part report on the Whisper. When I opened the Big Cat box, it gave me the same instant appeal--a lightweight air rifle with a stock made for adults. There are no high cheekpieces, no thumbholes or oddly shaped pistol grips to contend with. It's simply built right. If you enjoy a Winchester 1894 or a 1903 Springfield, the Big Cat just may be the spring-piston breakbarrel for you.

Wanna know another reason I'm looking at this air rifle? Because, as of this morning, it has 50 reviews on the Pyramyd Air website and an overall rating of 4.5 stars! That's incredible! There are guys who wouldn't give a five-star rating to a million-dollar cash prize and a date with Cameron Diaz. They'd complain about the taxes and having to get dressed up! So a half star down from the top IS the top on our survey. And I wanted to see just how nice a $140 scoped spring-piston rifle could be.

You're going to have to take the scope with the rifle because that's the only way it comes. There are no open sights on the gun. I think a good analogy for the Big Cat is a Whisper without the silencer. It's about a pound heavier at just over 6 lbs., which makes it a featherweight spring gun in this power class. It has a synthetic-jacketed barrel that's sculpted with deep flutes running nearly the full length of the barrel. The dark gray synthetic stock is a smooth with a pebble finish on the forearm and pistol grip. The butt has a thick, black ventilated recoil pad that grips your shoulder well. I like the low cheekpiece and comb that allow me to get down on the gun when I'm aiming.

The scope rail grooves are cut into the mainspring tube, and Gamo drilled a rear scope stop hole--bless their hearts! So any scope mounts that have a vertical scope stop pin will work. This airgun has the earmarks of a very well-designed spring rifle.

The trigger
I have to comment on the Gamo trigger on this particular test rifle--and maybe this is happening on all Gamo rifles these days. Although the design doesn't seem to have changed, the finish of the parts has improved significantly. That means the creep that used to be there is reduced by quite a lot. This Big Cat's trigger is a very crisp two-stage unit that worked just as well right out of the box as a vintage Gamo trigger with several thousand shots on it. The second stage still has some creep, but the overall performance is many times better than other Gamo triggers I've tested.

The trigger on my test rifle breaks very consistently at 4 lbs., 3 ozs. And that's when it's brand-new. No doubt it will drop a few ounces and smooth out even more during the break-in.

The safety is manual, thankfully, so all you do is cock, load and fire the gun. But Gamo has installed an anti-beartrap mechanism that prevents firing the gun until the barrel is closed, so de-cocking isn't possible. In this litigious age, that feature is almost mandatory.

Cocking
And cocking is another revelation I must share with you. The Big Cat has an articulated two-piece cocking link that lets the barrel break back to an extremely acute angle. The result is a long, easy cocking stroke. Gamo engineers have obviously studied their physics and applied them to the geometry of these new rifles.

The powerplant has very little in the way of vibration during the firing cycle. Things are over quick, and the rifle is quiet afterwards. I can't help wondering how it would be with an Air Venturi Ram Air gas spring installed, but I have nothing but praise for the way it works in factory trim.

The scope
The 4x scope is a cheap one, as you knew it had to be to allow the package to sell at such a low price. That said, the scope seems clear and will certainly do the job until you're ready to spend money on something more expensive. I'll use it for the accuracy test, so you can see its capabilities. And please don't ask me to repeat the test with a more powerful scope so you can see the incremental improvement!

The two-piece scope mounts have caps with two screws each, but they seem more robust than average mounts. They have the required vertical scope-stop pin and come attached to the scope. All you have to do is attach their bases to the rifle and tighten the base screws--not more than a 5-minute job for a new shooter.

What are you saying, B.B.?
Just so you're clear on this, I'm saying that now that I've handled the Gamo Big Cat, I'm beginning to understand why it got such a high rating from so many shooters. I'm saying that if you're in the market for a budget breakbarrel, the Big Cat MIGHT be one to consider. I'll reserve the final judgement, just like the rest of you, until I see the numbers and the targets. But I have a hunch this is a good one.

Field target for the rest of us

noreply@blogger.com (B.B. Pelletier) — Fri, 02 Jan 2009 11:30:00 +0000

Hi, guys. I DID have a blog for today...but, when Edith showed me this one, I realized this was the perfect Friday "get the gab started" piece. For those who don't remember, Edith is Mrs. B.B. Pelletier, and she's giving me the day off.

by Edith Gaylord (Mrs. B.B.)

Tom used to be the match director for the field target club we helped start at our Izaak Walton League in Damascus, Maryland (often called the "Dam Ikes"). I didn't participate in the matches but was happy to register the shooters, collect the money, recheck the score sheets and post the match results on our website. Well, I was uninterested in shooting field target until they invented the Wacky Match!

No rules...just right
The Wacky Match was a field target match that had no rules. You might say it was an unmatch...or even a mismatch.

It didn't have a lot of participants because most field target shooters are serious about the sport. They'd invested a significant amount of money into their guns and gear, and some had spent several hours on the road to get to the match. It wasn't a time for silliness.

The targets were set up the morning of the match, which was a half-size match. We wanted to finish early enough to enjoy the cookout provided by the club. It was their way of thanking the shooters for supporting them during the match year.

My weapon of choice
A shooter could use any airgun (20 ft-lbs or less...to preserve the targets), scope, sight or support he wanted. I selected a Sharp U-SL CO2 rifle with a thumbhole stock. I'd shot it before in our basement and really liked how it felt, it came easily to my shoulder and it was more accurate than I was (not a great feat, but still important). I used open sights because I don't especially like scopes (more on that in a future blog). I had spare CO2 cartridges in my pocket and kept my pellets in a pouch hung around my neck. I traveled light and was ready for anything. Oh, yes, there was one more piece of equipment.

I brought a chair, because I wanted to sit while shooting. This was a special chair...one that I'd used while shooting BRV (which I'll write about at another time). It's comfortable, collapsible and steady on uneven ground. The first Wacky Match was held in October, and the ground was moist. I don't like sitting on icky, wet ground covered with creeping critters I can't identify and who-knows-what hiding under the damp leaves.

Here I am holding a great little airgun. I LOVE this Sharp rifle. It's lightweight, not very long, powered by 12-gram CO2 cartridges and--most importantly--quite accurate.

No one's keeping score
The foundation of the Wacky Match was that everyone was a winner. This was about fun, not results. Yet, I remember what I shot. I smacked a number of target faceplates, which didn't count as hits, and knocked down only two targets (yes, I had a score of 2 out of 30). I bet I could have done better if I'd thrown rocks! Thank goodness I'm a better shot when it really counts...with my .45 ACP.

I didn't shoot in all of the Wacky Matches because CO2 isn't cold-friendly. One Wacky Match was held in January, with a fresh layer of snow...and then it started snowing during the match! Come to think of it, I should have shot that match...it would have been the perfect excuse for such a low score. I guess I really am an airgunner--always blame the equipment!

2008 in review

noreply@blogger.com (B.B. Pelletier) — Thu, 01 Jan 2009 11:30:00 +0000

by B.B. Pelletier

Happy New Year! I'd like to thank everyone from around the world who wished us a Happy New Year on this blog. This one will be a quickie.

2008 was a real good year for airgunning, but before I look at a few of the highlights, I have some super news for those who are looking for good deals. These are models that are being discontinued; after the guns in stock are gone, there will be no more. Pyramyd Air has also cut the prices of both models quite a lot.

RWS 46 Stutzen. Down from $536.25 to $399.99.

RWS Diana 52 Luxus. This is the walnut-stocked version with basketweave checkering. These are available in both .22 caliber and .177. Pyramyd Air bought out the remaining stock from RWS and expects to receive them soon. Down from $595.00 to $419.99.

2008 started off with a big bang for me because the Benjamin Discovery was about to be launched. I took the concept for the rifle to Crosman a year before and I worked with them throughout 2007 to make the new rifle a reality. Now, at the start of 2008, I was about to travel to the SHOT Show where it would be unveiled.

The Disco, as it has become known, is the best entry-level PCP ever made, in my opinion. It has the benefits of price, a 2000 psi fill level, dual-fuel capability, and many other high-grade features packed into a neat package. In fact, the package with a hand pump was part of my original concept. The gun comes to you ready to shoot. I've wanted a gun like that for two decades, and now it exists.

Air Venturi gas springs also made a big splash this past year. I actually began testing them back in December 2007, which is when I tested the incredible Gamo Whisper with a gas spring. That rifle continues to be the smoothest gas spring conversion I've ever tested...bar none! I then tested the Webley Patriot with a gas spring--the rifle made in the UK, that is. I raved about how smooth the gas spring made the gun, but then you readers took things even farther when you started talking about the Walther Falcon Hunter with a gas spring. You said the gas spring changed the nature of the gun, which they will do.

I continued to test Gamos with gas springs and even today I'm far behind the power curve in that testing. But gas springs are here to stay!

In the middle of the year, Leapers brought out their new scope base for RWS Diana spring rifles. I'd also worked on it in 2007, similar to the Discovery. Instead of something brand new, this base was the answer to a question that I had been dealing with since I began writing about airguns in 1994. Namely, how to mount a scope on an RWS Diana spring rifle.

The new base tested well, but as they were sold we learned that not all rifles suffer from barrel droop. In fact, the RWS Diana 350 Magnum rifles don't seem to have much droop at all. So, Leapers rushed to create a base with zero droop. And by the end of the year, there's a scope mounting solution for all RWS Diana spring rifles except the model 46, which doesn't have the same base on the receiver. This new Leapers base has become an important part of a spring airgunner's tool kit.

I also tested both the Evanix Renegade rifle and the pistol for you last year. They offer a greater number of shots and fast double-action shooting for those fast follow-up hunting shots. Air management with the rifle is quite good, and accuracy is certainly where it needs to be. There are still two Renegades yet to be tested in 2009.

The AirForce Edge target rifle didn't make it to market in 2008, but the sight set almost did. I got to test both front and rear sights, and we know that a great alternative to the $400 European sights is coming down the pike.

So, where are we headed?
I have a few projects coming in 2009, too. One is a new kind of pellet that, if it works as envisioned, should impact hunting in a positive way. I'm also associated with the development of a new type of powerplant that promises huge gains in efficiency. And there's another project that I will announce in two weeks--on day one of the SHOT Show. That project, which is as real as it gets, could change the lives of American airgunners in a very positive way.

Understanding the performance/power curve of a PCP

noreply@blogger.com (B.B. Pelletier) — Wed, 31 Dec 2008 11:30:00 +0000

by B.B. Pelletier

This final blog of 2008 was inspired by several questions from reader Kevin but also from other readers who are now owners of precharged pneumatic (PCP) airguns. I've written these things before, but perhaps never put them in the same order as I will today.

A PCP valve operates best between a certain high and low pressure point. That is to say the valve will open and remain open long enough to pass air from the reservoir to power a pellet to more or less the same velocity. When the reservoir pressure is high, it acts on the valve to close it faster, but the air that passes through the valve when the gun fires is under a lot of pressure. As you continue to shoot and the reservoir pressure drops, it acts with less force and less quickly on the valve to close it, so the valve remains open slightly longer. The air that passes through the valve before it closes is not pressurized as high; but since the valve remains open slightly longer, it delivers similar acceleration to the pellet. The result is that the pellet stays at the same velocity, more or less, throughout a number of shots.

The string of shots that are at the same velocity are the power curve of the gun. If the reservoir pressure is above the pressure at which this power curve begins, the shots will be slower. If the reservoir pressure is below the pressure at which the power curve ends, the shots will also be slower.

On either end of the power curve--before the curve begins (pressure too high) or after it ends (pressure too low), the pellets will exit the muzzle at a lower velocity than when the valve is dealing with pressure that's inside the power curve.

As a gun that has been over-pressurized is fired, it loses some pressure with each shot. The pellets will come out progressively faster as the pressure drops, and you can actually record this if you have a chronograph. Then, at some point the velocity seems to stabilize at a level of similar velocities for several shots. That area is the right pressure for your valve and therefore for your gun. We call that area the power curve because it represents the place within the whole pressure curve (zero psi to the maximum fill pressure) at which the rifle operates the best--and also at the same power (more or less).

As you continue to shoot and the pressure in the air reservoir drops below the ideal operating pressure, the velocity of the pellets starts dropping below the ideal range. The decline can be either a straight decline with each new shot or the velocity can go up and down, but it's always headed in a general downward direction. A powerful gun like the Career Infinity will usually drop velocity straight down with every shot when it falls off the power curve, while a less powerful gun like a Benjamin Discovery may have velocities that go up and down; but the general direction will always be down from the ideal level (the power curve).

So, with yesterday's 12-shot string that was continually declining with each new shot, I concluded that the rifle was coming down off the optimum power curve--a curve that would have been even higher than the 3,300 psi I put into the reservoir at the beginning. That's why I said this in yesterday's blog:

It seems as if the gun's maximum fill is still higher than 3,300 psi, but I don't have the pressure to go there. Nor do I think I would if I could. I've seen the walls of the reservoir, and they aren't that thick. I recommend you do not overfill this rifle, because I don't think there's a large margin of safety. I did it to demonstrate that the valve was not yet on the power curve.

Do you understand? My last sentence, "I did it to demonstrate that the valve was not yet on the power curve" refers to pressurizing the reservoir to 3,300 psi after testing the rifle at 3,000 psi. Since each shot declined in velocity with a 3,000 psi fill, I boosted the pressure to demonstrate that the velocity would go even higher. I'd hoped the first couple of shots would be close to the same velocity with the 3,300 psi fill, but you can see that they're not. Of course, that's not to say that 3,300 psi isn't the exact point at which the rifle drops off the power curve, and if I had pressurized the rifle to 3,400 psi I might have gotten those few close shots I was looking for. We'll never know, because I don't feel confident pressurizing this rifle any higher.

Kevin also asked why I said this--"the valve cannot function with pellets this heavy." I was referring to some guns that will never have a power curve with pellets over a certain weight. You didn't notice it because I didn't report the shot strings. When I went to the lighter pellets, I got some shots of similar velocities. That was with the power wheel set on the lowest power setting. The rifle is very clearly on the power curve with lighter pellets and a lower power setting.

So, Kevin, the velocities I saw told me that this Infinity was not on the power curve with Eun Jin pellets, but that it was very much on the power curve with both Crosman Premiers and Air Arms Diabolo Field pellets. With the lighter pellets, I manipulated the power adjustment wheel to keep the gun on the power curve longer.

Kevin asked what I meant by a "broad flat spot on a power curve." In this case, my answer looks better as a picture:

This is a typical velocity-over-pressure chart for a PCP. You get this by chronographing all the shots in a fill. If they look like this, you've captured the power curve, which begins at shot 15 (2600 psi) and ends at shot 27 (2150 psi). Filling this gun beyond 2650 psi is a waste of air, as is shooting after the 13th shot.

And, Kevin--every pressure above 2650 psi with this particular airgun is entering into valve lock.

Now you know it all!

Career Infinity by Shin Sung - Part 3

noreply@blogger.com (B.B. Pelletier) — Tue, 30 Dec 2008 11:30:00 +0000

by B.B. Pelletier

Part 1
Part 2

Let's look at the Career Infinity velocity. The new inlet seal I showed you yesterday is working fine, and it may turn out to be the fix for this problem. I'll let you know at the end of the accuracy report, when the gun has been filled many more times.

You may recall that this gun doesn't shoot the pellets from the cylinders. It pushes them into the breech with a bolt probe, and that's where they are fired from. That way the long gap from cylinder to breech is a non-issue, as far as accuracy goes. The pellet begins its flight while already in contact with the rifling.

However, there are two observations I will make about the cylinders. First, they do not rotate far enough to align with the bore during the cocking stroke. After cocking, I had to advance the cylinder another half turn to get the pellet chamber aligned with the bore. You know that because the bolt probe won't align with the chamber in the cylinder, which prevents the sidelever from closing. That held true for both cylinders that came with the gun, and it takes away some of the speed you get from the rifle being a repeater.

The second thing I noticed about the cylinders is that it's possible to insert them into the receiver backwards, with the tails of the pellet pointed forward. If you do that, the pellets still feed into the barrel and still fire normally. Remember to load the cylinders with the outer spring to the rear.

Cocking is easy enough. It isn't exactly smooth, but the sidelever allows a powerful hammer spring to be compressed with reasonable effort.

The safety is, thankfully, manual. It's always there if you need it, but you don't have to fumble with it if you don't want to. It's easy enough to put on and take off with just the trigger finger.

The onboard pressure gauge reads in bar instead of psi. I found the one on the test gun reads about 25 bar low, so 3,000 psi reads as 175 bar instead of 206.

There's a power adjuster on this rifle. There are four spots on the power wheel located in front of the triggerguard and there are a total of 12 positive click detents from lowest to highest power. Since that presents a lifetime of possibilities, I decided to limit the settings based on the pellet being used and how the air was holding out. With heavyweight Eun Jin pellets, I used the highest setting; with medium-weight Crosman Premiers and Air Arms pellets, I used the lowest setting.

Eun Jin
The Eun Jin pellet weighs 28.4 grains, nominally. With a fresh 3,000 psi fill, I got the following results with the first six shots:

985 fps
986 fps
965 fps
957 fps
949 fps
937 fps

That tells me the rifle is not on the power curve at 3,000 psi. It could also be that the valve cannot function with pellets this heavy. I then filled it to 3,300 psi and got these results:

1017 fps
1011 fps
1001 fps
998 fps
987 fps
979 fps

971 fps
962 fps
952 fps
944 fps
927 fps
924 fps

It seems as if the gun's maximum fill is still higher than 3,300 psi, but I don't have the pressure to go there. Nor do I think I would if I could. I've seen the walls of the reservoir, and they aren't that thick. I don't recommend overfilling this rifle, because I don't think there's a large margin of safety. I did it to demonstrate that the valve was not yet on the power curve.

Also, the way the valve is constructed, each shot will decline in velocity. This rifle has no broad flat spot on the power curve, like many PCPs do. However, I wouldn't shoot it this way if it were my rifle. Instead, I'd use the abundant number of lower-powered shots it offers.

Plenty of good shots at low power
On the lowest power setting, a fresh fill gave 6 strings of 6 shots between 927 f.p.s. and 1068 f.p.s. with 14.3-grain Crosman Premiers and 16-grain Air Arms Diabolo Field pellets. That's a total of 36 shots at that velocity range on low power from a single 3,000 psi fill. Taking a central 1,000 f.p.s. as the average for the 16-grain Air Arms pellets, that's 35.5 foot-pounds.

To get the last string, I bumped the power wheel up to the yellow level, which is three-quarters full power on this gun. The shots were still falling off rapidly, as you see here:

996 fps
983 fps
967 fps
954 fps
938 fps
927 fps

Maybe 30 shots is more realistic than 36, but that's a lot of very powerful shots with what may well turn out to be the most accurate pellets. As a practical hunting gun, you either get 12 shots that average about 60 foot-pounds or 30 shots averaging 36 foot-pounds. That makes the Infinity one heck of a good hunting rifle!

The single-stage trigger breaks after a lot of creep at a light 2 lbs., 10 ozs. The trigger blade is too curved for my taste, but I can't deny that it's lighter than the triggers of 99 percent of all unmodified rimfires.

There's a lot of intrigue to this rifle. Now that the inlet valve has been fixed, we're going to see what it's capable of. Next time, we'll look at accuracy.

Odds and ends Removing the Diana 27 seal & fixing the Infinity inlet seal

noreply@blogger.com (B.B. Pelletier) — Mon, 29 Dec 2008 11:30:00 +0000

by B.B. Pelletier

It's too cold to shoot CO2 outdoors, so the accuracy test of the Crosman 1088 is postponed until we get some warmer days. So, I thought I'd clean up a couple of jobs that I'm working on and show them to you as I go. First, I removed the leather breech seal from the Diana 27 rifle.

Derrick found an inexpensive set of leather punches for me at Harbor Freight, so I ordered them to use in the Diana 27 breech seal project instead of just carving the seal from a leather belt with a sharp knife. There are nine graduated punches in the set for less than $5, so even with shipping I figured it was well worth the investment. I'll probably have to trim the seal to final size, but the punches will get me most of the way there.

Today I decided to remove the old seal for you, so you can see what the job looks like. Several months ago, I bought a set of dental picks to use on the Walther Falcon Hunter breech seal I replaced during that test series, and they worked well for this seal, as well.

These picks were inexpensive, and they make handling breech seals easy. On this job, I had to break the seal into pieces and scrape it out of the channel.

Old seal was brittle
The old seal came out in chunks instead of a whole seal. That happens only
when the leather has lost all its sealing properties and has transformed into a waxy mass of dark stuff. It should have hung together, but the leather was shot. That happens when there's no lubrication for a long time--maybe decades.

When the old leather seal is completely removed from the Diana 27 breech, you can see the groove the new seal must fit. This photo is like an Escher print until you decode it in your mind. We're looking at a breech that's pointing up--away from us. The groove for the seal is wide and flat and there is a stub of the barrel in the middle. Notice that this shot shows more of the rifling, though a couple lands and grooves at 9 o'clock are invisible.

Weihrauch breech seal possible
Just for fun, I pressed a Weihrauch synthetic breech seal into the groove and it fit. It's about double the height it has to be for this gun, so I would have to divide it in half before installing, but I think it would work. But I want to try to fit a new leather seal to keep the rifle looking vintage.

I cleaned out the breech seal groove with the picks, so the groove is fresh for a new seal. A toothbrush was used to remove the smaller pieces of disintegrated leather.

That project is now on hold until the punches arrive, so I shifted over to the Career Infinity project. You'll remember that I replaced the inlet seal on my test gun, but then that seal started leaking, too. Boris made a Teflon seal to replace the brass seal holder in the gun.

Boris made the Teflon inlet seal on the left to replace the three-part inlet seal assembly that came with the rifle. Less mass may keep the seal from deforming too much.

The new seal is lighter and moves very smoothly inside the valve body. Being Teflon, it'll deform and take the exact shape of the valve seat. Hopefully, that'll fix the problem of the inlet valve dumping all the air after a fill.

When I filled the gun it held perfectly, but it also did that after the last seal replacement. The proof of the fix will be if the seal continues to hold after repeated fills, which I will be doing as we move into the velocity part of the test. Boris thought that the Teflon seal would be so light that it wouldn't get pushed out of shape like the brass carrier did to the factory seal. We shall see!

Diana 27 - Part 2

noreply@blogger.com (B.B. Pelletier) — Fri, 26 Dec 2008 11:30:00 +0000

by B.B. Pelletier

Part 1

Today we'll look at my .177 Diana model 27 rifle after the piston seal and breech seal have been soaked in oil. I told you I put petroleum oil down the air transfer port because my gun is a low-powered springer with leather seals. Leather seals need lots of oil to keep them fresh and pliable, and a low-powered springer doesn't generate enough compression to detonate the oil. So, petroleum-based oil is fine for guns on this category.

The way to know for certain that you've oiled the piston seal enough is to move the barrel through the first few inches of cocking and then relax it. Do that several times and listen carefully to the air transfer port. When you can hear a slurping sound coming from the port, the piston seal is soaked with enough oil to rejuvenate it.

My .22-caliber model 27 that I tuned about 10 years ago with lithium grease on the mainspring still slurps when I test it, despite never having been re-oiled all that time. The excess lithium grease has soaked the seal from the back, making that tune a very long lasting one. However, I did use so much grease on the spring that I gave up some power with that rifle. I think when I tune this one I'll use black tar grease on the mainspring and oil the piston seal conventionally.

When I oiled the leather breech seal on this 27, it started to disintegrate. I took a closeup photo to show you what that looks like. This seal doesn't look too good to me, but looks can be deceiving. The chronograph test should tell us for certain if the seal still works. I cannot feel a blast of air coming from the breech joint when the rifle fires, which is one test for an air leak. But a chronograph test should be conclusive.

You can see the disintegration of the breech seal in this photo. Bits of leather are sloughing off, leaving pits where there should be a raised surface. An oil spray can be seen rising from the breech with every shot. Even though I can't feel anything, that oil spray confirms the fact that the breech seal is shot.

I also felt the barrel on this rifle deserved to be cleaned with J-B Non-Embedding Bore Cleaning Compound. Even though the velocity is not high enough for leading to be a problem with any pellet, we don't know the history of this rifle. If there's anything in the bore that could hurt velocity or accuracy (probably accuracy more than velocity), I want to clear it out. We'll start with a fresh new bore.

The bore seemed easy to clean, and there's a definite choke at the muzzle end. The breech was very dirty. After cleaning, all pellets loaded easier than they did during the first test. Now, let's see how the velocity is affected after oiling both the piston seal and the breech seal.

Eley Wasps
Before oiling Wasps averaged 444 f.p.s. After oiling and some sloughing of the breech seal, the average is 225 f.p.s. The breech seal is visibly leaking.

RWS Basic
RWS Basic pellets had averaged around 475 f.p;.s. before (they were very bi-modal, so I recorded two averages) and 212 f.p.s. after. The breech seal has failed.

Crosman Premier 7.9-grain pellets averaged 580 before and 321 after. In fact, only RWS Superdomes held anywhere close to their former average of 412 f.p.s., coming in close at 393 f.p.s.

Well, that wasn't a very big surprise, given the shape of the breech seal. The big question now is what does the piston seal look like. In my experience, leather breech seals fail sooner than piston seals, but we'll have to tear the rifle apart to know for sure.

The firing behavior has become rougher, which is the piston slamming into the end of the compression chamber because the air is leaking so badly at the breech. I hope I can save the piston seal, but a new breech seal is mandatory.

I adjusted the trigger, which is the rear screw only. The front screw is just a locking screw, and the rear screw controls how crisp and light the trigger pull is. I screwed it down pretty far, which made the second-stage pull very crisp. The drawback is a longer first-stage pull, but there's no way around it if you want a crisp second stage.

This photo is worth a lot to vintage Diana owners. The rear screw (at right) is down nearly all the way, and the front screw is tight. This gives a model 27 a crisp two-stage pull.

The next report will be either a disassembly of the powerplant or the repair of the breech seal, whichever comes first.

Merry Christmas 2008

noreply@blogger.com (B.B. Pelletier) — Thu, 25 Dec 2008 11:30:00 +0000

by B.B. Pelletier

Merry Christmas!

I was interviewed on the Arizona radio program, America Armed and Free last week. You can listen to that interview here, if you like. It will be available for one more week.

Today I'll share a couple of my favorite gifts with you, and maybe you readers can let us know what you got. For those who don't celebrate Christmas, you can either tell us about your most recent acquisition or just sit back and enjoy the party!

The man who has everything
What does Tom Gaylord's wife give him for Christmas--the man with the entire airgun world at his fingertips? While that's not entirely true, a lot of people think it is. They think I can have anything I want.

The truth is, I'm a lot like the rest of you. I do get to test a lot of exotic airguns and related stuff, but my own collection is based more on reality.

However, this year I asked for firearm reloading equipment. Now that my wife and I are shooting 100-200 rounds of .45 ACP every month, I can no longer keep up with my Lee 1000 turret press. So I asked for and received a Dillon Square Deal B press that makes 400-500 cartridges an hour without rushing. Instead of three hours of reloading I will now spend one hour at most to get better ammo than ever before! I also got a bunch of accessories that weren't included in with the press.

Dillon Square Deal B progressive reloading press makes up to 500 cartridges per hour with minimum effort.

Airgun gift?
I didn't receive any airgun gifts from the family this year, but I did get a peach of an aperture sight from reader Kevin, who wanted me to try it on a Diana 27. I plan to test it for you in a special report, but I wanted to show it to you today, because it is my one airgun gift this year. And isn't it sweet? My thanks to Kevin for this beautiful sight.

Kevin sent me this beautiful Diana aperture sight that will fit on a Diana model 27. It has a neat feature about it that Diana owners should know about. I will review it for you in detail.

I'm stopping here, but I want you guys to take over and tell us what you got. I'll be back tomorrow.

Buying a high-pressure air tank - Part 2 1000 posts!

noreply@blogger.com (B.B. Pelletier) — Wed, 24 Dec 2008 11:30:00 +0000

by B.B. Pelletier

Part 1

Today's post is the thousandth since we began in March 2005. How fitting that it should come on Christmas Eve. Regardless of your religious views, we all owe Pyramyd Air thanks for their gift of this blog that has lasted so long. Let's hope we'll still be enjoying it after another thousand reports!

Although Abe asked for this report, I've heard from a lot of other readers who had questions and comments about air tanks. I'll try to address them all today.

Lloyd wants me to tell you that you should buy the largest scuba tank you can afford. He also says to tell the dive shop operator to please fill the tank to the max, because divers are less concerned with pressure than we are. His most important message, though, is to get to know the people at your dive shop. I couldn't agree more. I've seen airgunners ruin their entire PCP arrangement by simply alienating the dive shop personnel. And I've gotten many concessions and good treatment because I acted as though the dive shop was doing me a favor--WHICH IT IS. A little civility goes a long way when dealing with an owner/operator, like the guy who runs the dive shop.

Lloyd also asks if dive shops are the only place to get a 4500 psi fill. Well, I think they are the WORST place! I go to a paintball shop, because my dive shop fills me to only 4,000 psi or so. That's all his air system can produce. Sometimes, you can get a fill from the local fire station. It helps if the firefighters are also airgunners or maybe you take them a couple dozen donuts when you go there. Like I said, some guys can do it and others can't. Ask yourself, "What would Wayne do?" when you go, and you'll probably get what you want.

Jony wants me to remind you that a smaller tank at higher pressure is often better than a large tank at lower pressure. The proof of that is the fact that a 2,200 psi tank won't even give you one fill of your AirForce Talon SS, despite being just as physically large as an 80 cubic foot aluminum tank that gets pressurized to 3,000 psi. In this game, pressure is king, and we either want tanks at higher pressure or guns that shoot at lower pressure. Having both is the best of all.

Pony tanks
A pony tank is a small air tank that divers and rescue workers use for convenience or for emergencies. We used them in the Army when fording rivers in our M60A1 battle tanks, because some of the crew members in the tank were 10 feet under water when the tank was driving across the river bed. If the air snorkel tube collapsed at those times, the driver could drown before he could get out of the tank. So, he used a pony air tank for a five-minute emergency air supply.

Big bore hunters carry carbon-fiber pony tanks to top off their rifles during a hunt. A small tank that fits in a backpack can refill even a large big bore rifle 2-3 times for a total of 6 additional shots. Any big-bore hunter will tell you that six shots is probably more than a day's supply for big-game.

When I competed in field target, I carried a 13-cubic foot pony tank to top off my Daystate Harrier. That rifle, which filled to 2,650 psi, got three refills from that little 3,000 psi pony tank. Since each fill was good for 24 shots, that was enough for almost 100 shots if you factor in the initial fill. A match typically has only 60 shots, so I was covered.

The Benjamin air tank is an example of a pony tank. Because it works on the Benjamin Discovery rifle which operates at 2,000 psi, it still gives plenty of fills.

Pony tanks have their place in PCP guns, but you don't want to buy one as your principal source of air.

Mr. B. says a day in the woods requires more shots than a Talon SS air tank can offer (maybe 35-45 shots at full power, depending on the range). Well, Mr. B., that Talon SS tank is actually a pony tank! Why not buy an extra AirForce standard tank? When your first one runs dry, just screw on a new one? That's how AirForce designed the gun to begin with.

Filling a gun from a tank
Abe asks about the proper way to fill a gun from a scuba tank, and I've had several other people ask the same thing. Here's a report I did on that subject. The first step is to connect the scuba tank to the gun. For this you need a fill adapter. One end connects to the scuba tank, the other connects to the gun. Both have to fit what they connect to, so you have to determine what it takes to do that. Scuba tanks and carbon fiber tanks have all kinds of valves. The most common scuba tank valve in the U.S. in the K-valve, but a DIN valve will sometimes be encountered. When the rated tank pressure goes above 3,000 psi, the DIN valve becomes more common. Your job is to determine what kind of valve your air tank has.

The K-valve is flat with an o-ring to seal it. This type needs a clamp that fits around the back of the valve to hold it.

A DIN valve has a hole with threads to accept any devices. This is the deeper 300-bar DIN hole, though both have the same diameter and threads.

A refill clamp fits around the K-valve.

Abe also asked about the scuba tank inspection process. That's not a part of this report, but I covered it here and also here.

Buying used
Sooner or later, it'll dawn on you that a used scuba tank would be cheaper than a new one. But what you don't know is that there's a very good reason for that. A scuba tank must pass a hydrostatic pressure test every five years. When they fail or when they get near the end of their useful life, they aren't worth buying. We had a reader who bought a used tank for $50, then had to spend $135 getting it back in shape. While that was a little extreme (he needed a new K-valve), a hydro and the other tests you need could easily cost $60. And you could wind up with a tank that fails its hydro, leaving you with nothing, because the testing facility will drill a hole in your tank to remove it from the market.

The best way to buy used is to buy from a dive shop you do business with. If there's a problem, they'll take care of you.

Diana 27 - Part 1

noreply@blogger.com (B.B. Pelletier) — Tue, 23 Dec 2008 11:30:00 +0000

by B.B. Pelletier

Diana model 27 is a classic breakbarrel. My new one is a .177.

Kevin prompted this report by asking me about the Diana 27 I bought at this year's Roanoke airgun show. Then he surprised me with the gift of a very nice peep sight made for the Diana model 75. It also works great on the little Diana 27 rifles, and Kevin wanted me to see that so he sent one.

What I plan to do is test my new .177-caliber model 27 and then install the peep sight and test that for you. Unfortunately, the 27 I got in Roanoke doesn't have a rear sight base for this sight; I'll install it on my other 27, which is a Hy-Score 807 in .22 caliber. For those who are fascinated by coincidences, the .22 caliber Hy-Score was purchased from the same dealer from whom I bought the .177 15 years before. It was made in August of 1967, while the new gun was made in March of that same year. Spooky, no?

The new Diana came without a rear sight rail. The presence of the Diana logo indicates there never was one.

Many Diana 27 rifles, including this Hy-Score 807, have a rear rail like this for mounting a peep sight.

The top of the rail is textured with cross-slots that assist the peep sight by providing a solid anchoring surface.

I'll test the new rifle before lubricating the piston seal and again after a good oil soak. The oil will be applied through the air transfer port, so no disassembly is required.

However, I thought this new rifle would also be the perfect one to tune for you so I can show you the inside parts and how I tune it. That's coming some time in the future.

Before oiling
But right now, we'll test the rifle as I got it. The 27 is a low-powered spring-piston breakbarrel that was considered medium-powered in its day. The rifle had a long life, starting in 1910 and running off and on until 1986. However, all those model 27 rifles were not the same model. In fact, you can't really call them the same gun. The model 27 we're examining here started some time after World War II and finished in '86. That said, the final pre-war 27 rifle was quite similar in appearance to the post-war gun and differed only in the trigger and a few small details. This particular rifle I'm testing was manufactured in March 1967 (from the date stamp on the spring tube).

Eley Wasps
Kevin also sent along a tin of .177 Eley Wasps for me to test. He says they're very accurate in his 27, and he wanted me to try them in mine. The .177 Wasp is a domed pellet that weighs 8.1 grains on average. It's a pure lead pellet. In .22 caliber, the Wasp is also sold in an oversized 5.6mm, but in .177 the head diameter is 0.174" and the skirt is approximately 0.181" to 0.183". I say approximately because these pellets vary a lot. Being pure lead, they deform when handled.

They fit the breech of this rifle very tight and had to be pushed into the bore with a Bic pen to avoid damage to the skirt when the breech was closed. If I didn't seat them, the velocity was 278 f.p.s. Seated they had a velocity of 444, but it was sharply bi-modal with the lower average at 436 and the high at 460. There was no shot recorded between the velocities of 439 f.p.s. and 456 f.p.s. I suspect an extremely dry piston and breech seal.

RWS Diabolo Basic
RWS Diabolo Basic pellets were even more sharply bi-modal than the Wasps, with a low average of 457 f.p.s. and a high average of 512 f.p.s. No shot was recorded between 460 f.p.s. and 505 f.p.s. These pellets were also tight in the breech and had to be pushed into the bore with a Bic.

RWS Superdome
The RWS Superdome was not bi-modal and averaged 412 f.p.s. The high was 425 and the low was 395. They were also tight and seated in the bore with the pen.

Crosman Premier 7.9-grain
Crosman Premier 7.9-grain pellets could be seated by finger pressure alone. And they averaged 580 f.p.s., with a spread from 560 to 593. On paper, they appear to be a promising pellet, but the target will tell.

I had the feeling after this testing that the leather piston seal and breech seal need copious amounts of oil. So, I oiled the piston seal through the transfer port and the breech seal topically. I'll repeat this process one more time and give the rifle a couple days to soak it all in. Then, I expect the results to be faster and more uniform.

We shall see!

IZH-61 magazine test

noreply@blogger.com (B.B. Pelletier) — Mon, 22 Dec 2008 11:30:00 +0000

Chuck is a reader who posted a lengthy comment about blind-testing a batch of IZH 61 clips. His methods were sound, so I asked him to turn it into a guest blog for everyone.

IZH-61 magazine test

by Chuck

I bought an IZH-61 for myself a while back and liked it so much that I bought one for each of my three grandkids. I had their 6 magazines and my 2 for a total of 8 magazines, so I developed a blind test.

I marked each gun and mag with each child's first initial in case a gun or mag got or lost so there'd be no arguing over whose it was. This made it easy for me to identify each magazine for the test, but only under close inspection because I used a black marker on the black mags.

Testing procedure
I assure you I did not know whose magazine I was shooting with, yet, after a batch of 8 magazines, I knew which magazine to match up with which target. Next, before shooting, I mixed up all the magazines and laid them out in the order of the targets. I then shot them in that order, matched and labeled them on their targets; I mixed them up again and shot another batch at 8 different targets. That was 2 batches of 8 magazines each, 5 shots per target, 16 targets, for a total of 80 shots, hence a fatigue and concentration issue. I had to concentrate harder on the second round of 8.

My range is indoors and 10 yards, I used the same Bug Buster scoped gun with Beeman H&N Match Wadcutters (8.0 grains). I used them because I had a lot, and I had previously weighed each one on an electronic scale.

Test results for batches 1 & 2
What I found was that a magazine that produced under 1/2" groups on the first batch of 8 magazines did worse on the second batch and vice versa. Of the 16 targets, all groups were 3/4" or better. Five were pretty close to 1/4". One magazine that did the worst on the first batch of 8 did the best on the second (must have been the pit stop).

The first 3 targets of each batch of 8 were inside 1/2"--I think due to my being more rested. The magazines that did not shoot inside 1/2" I re-shot after a rest period and got them inside a 1/2" (picture not shown so you'll have to take my word for it).

While shooting may not be physically fatiguing, it's definitely mentally fatiguing for me. I get what pro golfers call the yips, especially if I'm excited from shooting great groups. If you know any golfers, ask them about the yips. I'll bet you get shooters' yips, too.

The targets for each batch are numbered 1-8 and marked with the magazine numbers C1, C2, E1, E2, K1, K2, R1 & R2. The bullseyes on the targets are 1/2" in diameter.

Notice the strange location of target 8 (K2) on batch 1 (left target). Sorry for this sloppy batch, but I shot 2 warm up targets, then ran out of targets on this page so I aimed for the intersection of the lines formed by the block of four targets (2 practice--target 1 and target 3).

Note magazine R1 in batch 1 (target 5) has bad grouping while batch 2 (target 1) has good grouping. Next note that magazine K1 in batch 1 (target 6) has good grouping while batch 2 (target 5) has bad grouping.

Look at batch 2, target 4. Vertical stringing--that has to be me!

Test results for batch 3
The next day I did a similar test with just one batch of 8 magazines, but with a different pellet (no weighed). Ouch, I had somehow become a worse shot overnight. None of my groupings were as good as the night before. Three targets had fliers that went 2 or 3 rings out from center. Only one group was smaller than 1/2".

Test results for batch 4
I waited another day and tried the same test but this time with weighed pellets. I didn't have any radical fliers this time (or maybe they were all radical fliers) but all my groups were still larger than 1/2".

Wrap up
I then took 2 mags that had the worst groups and shot the same pellets with them. Still got bad groups. Well, you've probably guessed what my next test was. Yep, I went back to the H&N Wadcutters in those two mags and started shooting 1/4"-1/2" groups again. This doesn't necessarily mean the second brand of pellets are bad. It only means they're different for this gun or for me. I don't understand it, but it seems to be so. It could even be psychological if I think brand A is superior and my brain automatically concentrates better.

Conclusion
I believe my bad groupings in this test were due to lack of experience, shooter fatigue, lack of concentration, ill-spaced pit stops and/or pellet dynamics, and not magazine properties. When I gain more experience and find that pellet that is right for me and after my grandkids have broken in their magazines more, I will retry this test if for no other reason than my own amazement and amusement.

Post mortem
After completing my tests I took a close look at the mechanics of how the pellets are loaded into the gun barrel. In the IZH-61 owner's manual, Figure 1 shows a follower (item #8). It's a machined rod that is tapered toward the front, the part that goes into the receiver (item #44). The tapered part is about a half-inch long, smaller in diameter than the opening in the back of a pellet and is the part that rams the pellet into the receiver. The smaller rod also has a somewhat pointed tip that contacts the small indentation inside the skirt of the pellet to help guide it. The larger part of the rod is the diameter of the receiver opening. The rod is pushed forward when you cock the gun, and it shoves the pellet about 3/4" or so into the receiver because about 1/4" of the larger part of the rod goes in, too, to block any air blowback (I imagine).

It's my opinion that when the pellet is shoved into the receiver 3/4" by the rod, there won't be any influence on the pellet's orientation from the magazine at its final stopping position. However, I suppose a magazine could be defective enough to damage the pellet skirt in such a way that the movement into the receiver and down the barrel doesn't straighten it out. In that case, I think it would be easy to visually identify the defect.

You could argue that if a batch of magazines were bought, there's a chance one or more could be defective. However, at the same time, you could argue that one or more guns would have a defective magazine. I don't hear this coming from the multitude of IZH-61 owners (yet).

Bottom line
I had a whole lot of fun playing with this issue and fun is why I took up this sport in the first place. As an added bonus, I think I became a somewhat better shooter. I can't wait to see how a peep site will do on a test like this. Again, whoever it was who mentioned this in the first place, please come up with more thought-provoking ideas for me.

An outside-lock rifle by Gary Barnes

noreply@blogger.com (B.B. Pelletier) — Fri, 19 Dec 2008 11:30:00 +0000

by B.B. Pelletier

Sorry for the size of this image, but I wanted to show you the whole rifle, and Blogger only allows photo widths of 5 inches. The butt contains the reservoir and is covered with leather.

In 1998, Gary Barnes built a rifle that I consider to be his masterpiece. It more or less conforms to traditional lines, through it has an extra-long 16.5-inch pull that makes it suitable for a giant. The gun is unusual in many ways. First, it is .25 caliber. While not completely unknown in antiquity, .25 is really a modern airgun caliber.

Next, the 32.75-inch barrel is rifled. Rifled outside lock guns are unheard of because they date to as early as the 1600s and not much later than the mid-1700s before rifling was in widespread use.

Other curious features are the sights. They're made from mammoth ivory, a material sometimes used by knifemakers as a way around the elephant ivory that's illegal today. This prehistoric ivory sometimes resembles modern ivory with the patina of age.

Finally, the rifle is made as a breechloader. That is almost unheard of in an outside lock, though not entirely.

The rifle breaks open slightly for loading. This is most unusual in an antique pneumatic gun.

This antler loader is for seating pellets deep in the breech, which increases the muzzle velocity.

What do we mean by OUTSIDE lock?
What is an outside lock? Well it's a novel way of getting around physical laws without building an air rifle with an outlandishly large action. The action parts are attached to the outside of the sideplate instead of the inside. That allows the mainspring to stick forward into space and therefore be several times longer than the receiver had room. And that means it can be more powerful--which is one key to the outside lock's performance.

The outside lock has most of its action parts attached to the outside of the plate. The hammer spring can be larger than the receiver because it doesn't have to fit inside.

A customer of Barnes had sent him a genuine outside lock from the early 1700s and asked for some repairs. While he had the lock, he disassembled it and looked at every part, then made the lock and gun you see here. The lock he made looks remarkably similar to the original, and it functions exactly the same. Barnes made all the parts, including every screw that you see here. He made a trigger similar to the original but with one difference. His trigger ends in the center of the action and is usable by shooters who are either right- or left-handed.

Barnes lock at top and antique lock below. Barnes made the spring for the antique.

How does it work?
The outside lock is a marvel of engineering, because it is NOT a knock-open valve. Instead, it's the first true timed-release valve. The valve isn't knocked open. Instead, it's pushed open by a lever. That's why the mainspring has to be big and strong to overpower the valve and open it against the stored pressure. And this timing of the valve is another key to the gun's performance.

How are valves "timed"?
Once the valve opens, the hammer holds it open as it swings to its stop through an arc. If you look at the Barnes lock in the above picture of the two locks, you'll see a cam on top of the lever that pushes on the valve. It's at the top of the lever, which is located to the left of the hammer. When the hammer is cocked, it passes that cammed lever and swings way back to the left edge of the action. When the gun fires, the hammer passes the other lever, hitting that cam and pushing it forward at the top, which pushes it backwards at the bottom. The hammer and lever remain in contact for a long time as their two cams slide over each other, which holds the valve open longer. This is how they achieved the timing of the valve.

This drawing is scanned from Airgun Revue #4. The descriptions were removed because they're unreadable at this size and resolution, but you can see how the hammer interacts with the valve striker through the cams.

And what does a timed lock do?
The power of this gun depends on the shape of the two cams, the power of the hammer spring, the power of the valve-return spring, the size of the valve port, the air pressure inside the reservoir and the length of the barrel. The longer the valve is held open, the more pressurized air can flow out. The longer the barrel on the gun, the more time it has to act on the pellet. So, a timed lock also needs a long barrel to achieve its full potential.

Barnes' first hammer spring developed about 22 foot-pounds on a 600 psi fill, but it broke during operation. The second spring he made produced over 28 foot-pounds on a fill of 800 psi. That's right--just 800 psi and I got 12 shots from the gun. The first three were above 700 f.p.s. and the 12th shot was 462 f.p.s., when shooting a 20-grain Diana Magnum. A Beeman Kodiak would have almost certainly pushed the rifle over 30 foot-pounds, but the Diana Mags were the most accurate. Here are the exact velocities of all 12 shots:

713 f.p.s.
792 f.p.s.
795 f.p.s.
664 f.p.s.
635 f.p.s.
606 f.p.s.
581 f.p.s.
557 f.p.s.
539 f.p.s.
518 f.p.s.
495 f.p.s.
462 f.p.s.

The first shot illustrates a little bit of initial valve lock. My guess is the fill pressure is really best around 700 psi, but adding the extra 100 psi is not that harmful. However, it looks to me like another 100 psi would drop the velocity quite a bit, because that first shot is significantly lower than the second one. In the time before chronographs, the shooter relied on his ear and on bullet performance to indicate when to stop. Based on that, 10-12 shots seemed to be the limit.

Accuracy was about 3/4" for five shots at 10 meters. That was measured edge to edge across the widest dimension of the group. Because this is .25 caliber, it's actually a half-inch group. Not too shabby for open sights and a barrel that's nearly a yard long!

Alas, I no longer own the outside lock rifle. It was sold several years ago and is now in another collector's care. But that's how the world works. You never really own the vintage airguns you have. They're just yours for a time and then they pass on to someone else. If you think about it, that's how you came to acquire them in the first place.

Buying a high-pressure air tank - Part 1

noreply@blogger.com (B.B. Pelletier) — Thu, 18 Dec 2008 11:30:00 +0000

by B.B. Pelletier

This report is for Abe, but with the large number of folks coming into precharged airguns, I suspect many people need to read it.

When I started in precharged pneumatic guns (PCP) in 1996, the need for air was not as critical as it is today. The problems back then were overcoming the personal fears of high-pressure air, getting dive shops to fill the tanks for non-certified persons and, of course, adapters.

The adapter problem continues to be bad, though there are movements to standardize at Crosman, Daystate and in the aftermarket. But the tanks themselves are more critical now than ever before. That's because the guns of today need more air than they used to.

Size doesn't matter
Here is the problem. The physical SIZE of the scuba tank means next to nothing. What MATTERS is how much air it holds. You say, "Of course!" But until you become a PCP user, you don't really understand what that means.

The most common scuba tank
The standard scuba tank today is an aluminum 80 cubic-foot tank that's pressurized to 3,000 pounds per square inch (psi). The physical tank measures just under 30 in. high by about 7 in. in diameter. It weighs just under 40 lbs. when filled (mine weighs 38.5). All these specifications will vary slightly from manufacturer to manufacturer.

The most commonly used scuba tank in the U.S. is the 80 cubic-foot aluminum tank.

And it will completely fill a PCP rifle that needs 3,000 psi one to three times, depending on the volume of the gun's reservoir. AirForce rifles that have a huge 490cc air tank get about two complete fills from such a tank. Remember, I'm now talking about complete fills to 3,000 psi.

After a full fill come partial fills
After that, the rest of the fills will end at less than 3,000 psi, because the scuba tank's pressure has dropped. Taking an AirForce Condor as an example, each successive fill could look something like this:

2975 psi
2925 psi
2870 psi
2850 psi
2815 psi
2755 psi

And so on for about 15-18 fills. When the pressure in the scuba tank drops below 2200 psi, there isn't enough air left to fill the AirForce tank high enough to get the gun on the power curve. That means you have to get the scuba tank refilled.

Actual results will vary
The actual number of gun fills you get varies, based on how low you allow the gun's tank to decline before refilling and the size reservoir you're filling. So the numbers I've just given are approximations. Don't try to create mathematical formulae based on them--they're just general observations.

Get a bigger tank
If you want more fills, the solution is to get a tank that holds more air. In the scuba tank world there are aluminum tanks rated to hold 100 cubic feet of air at 3300 psi and steel tanks rated for 120 cubic feet of air at 3500 psi. Obviously, these tanks will give you more complete fills of any PCP than the 80 cubic-foot aluminum tank. The 100 cubic-foot aluminum tank is larger than the 80 cubic-foot tank, but the 120 cubic-foot steel tank is about the same size as the 80 cubic-foot aluminum tank. The 3500 psi steel tank weighs about five pounds more than the 80 cubic-foot tank. Both of these larger tanks cost more than the 80 cubic-foot tank. You have to look for sales when buying tanks like this.

Smaller is more
Then there are the tanks made of carbon fiber. They're actually aluminum bladders wrapped with carbon fiber fabric. They seem to be contradictions, because they're smaller and lighter than 80 cubic-foot aluminum scuba tanks, yet they hold more air. My 88 cubic-foot tank is 24 in. by 7 in. and weighs about 20 pounds when filled to 4,500 psi. It will completely fill the AirForce reservoir perhaps 7 to 9 times and will get many more partial fills than an 80 cubic-foot scuba tank. It costs several times as much as an 80 cubic-foot tank. So, as with most things, you pay for performance.

Carbon fiber tanks are rated to hold breathing air, but for land operations. They are most often encountered in rescue service operation.

So far, all I've talked about are the largest portable air tanks. That makes what I'm about to say meaningful. If I were shooting a big bore rifle that gets two or three shots per fill and needs 3,000 psi to be completely filled, an 80 cubic-foot tank would be inadequate. The tank that most smallbore PCP owners use today could not supply the air needed to keep a big bore operating very long.

But if I had a Benjamin Discovery rifle that has a maximum fill of only 2000 psi, an 80 cubic-foot scuba tank would be great! I would get a great many full fills and lots more partials from that tank. That's why I pushed hard for the 2000 psi fill level when we developed the Discovery. Besides being easier to fill with a hand pump, it extends the use of scuba tanks many times.

Okay, Abe, that's the first part of the report. Next week I'll cover smaller scuba/carbon fiber tanks, tank valves and buying used. What I need YOU to do is ask me questions now so I can work the answers into the next report. The same goes for all readers who have questions.

Crosman 1088 - Part 2

noreply@blogger.com (B.B. Pelletier) — Wed, 17 Dec 2008 11:30:00 +0000

by B.B. Pelletier

Part 1

Before I begin, here's an update on the Career Infinity. I wanted to test velocity for you today, but when I picked up the rifle it had leaked off a little, so I topped it off with the scuba tank. When I bled the line to disconnect from the tank, the inlet valve stuck open and exhausted all the air again. This was the same problem the rifle had before and fixed in the last report.

I called Boris at Pyramyd Air, and we talked about the problem a bit. Boris told me he has seen this happen a couple times. What's happening is that the inlet valve isn't returning to the exact spot it was before it opened, so a small passageway remains open for air to escape. The soft valve material allows that to occur. He thinks a Teflon valve may solve the problem because it would be lighter than the brass valve body that's in the gun now, plus Teflon conforms to almost any surface with a minimum of fuss. He's getting a new Teflon valve out to me. I will let you know how well it works when I get it installed.

Today, we'll look at how the Crosman 1088 pistol performs for velocity. The temperature outside is 27 degrees F, but in my office it's a toasty 70 degrees.

Load up!
The first discovery is that it's best to remove both grip panels to load a CO2 cartridge. You need to gain access to the screw key, and the grip panels get in the way. Yes, I applied Crosman Pellgunoil before piercing the cartridge.

I think I discovered why owners are tightening their cartridges too tight and causing leaks after a while. This gun loads silently. You cannot hear the gas rushing in. I finally stopped when I knew I had turned the key enough (really too much) and sure enough there was gas in the gun. For some reason, this is a quiet gun. Probably due to a new seal at the piercing pin. At any rate--watch it!

Crosman Silver Eagles
Let's get the speed-demon pellets out of the way. Crosman Silver Eagles went an average of 440 f.p.s. in double-action and 410 in single-action. The pellets I used were not the hollowpoints that weigh 0.2 grains less, so there might still be more velocity in the gun.

Beeman Kodiaks
Somebody asked me to try Beeman Kodiaks for accuracy in this pistol, so I also clocked them. They averaged 291 f.p.s. in double-action with a spread from 283 to 306. Single-action was 277.

No single-action
At this point, I discovered that the 1088 does not like to be fired single-action. At least the test gun doesn't. The hammer is only for firing. When you cock it, the clip doesn't advance to the next chamber. Only the trigger advances the clip. Several times the hammer released before the clip rotated, and I either shot a blank or I tied up the gun's action. I have to recommend you don't shoot it any way but by pulling the trigger. The Crosman website states the gun can be shot DA or SA, but the manual states that you fire the gun by pulling the trigger and does not mention cocking it with the hammer. We've emailed Crosman to get the facts on this. I'll update you when I find out.

RWS Diabiolo Basics
RWS Diabolo Basic pellets averaged 324 f.p.s. They ranged from 317 to 328.

Benjamin Sheridan Diabolo domes
Benjamin Sheridan Diabolo domes (7.9-grains.) went from 353 to 322. They score an average of 335 f.p.s. That's odd, since they're nearly a full grain heavier than the Basics that went 11 f.p.s. slower, but that's what happened.

Crosman BBs
The 1088 is also a BB gun, and, as a reader pointed out to me in the first report, a magnet holds the Crosman Copperhead BBs in the clip instead of the ridges down the inside of the chambers that I mentioned in my report. The BBs averaged 368 f.p.s. and ranged from 388 down to 348. However, they exhibited the same drop in velocity, shot after shot, that the pellet did. When shooting the BBs, I took pains to allow only five seconds between shots. Here's what that looks like:

388
386
371
367
361
358
348

Then, I waited a full minute before shooting the last shot.

353

The velocity drops with every shot when a five-second interval is used between shots. That means this gun is very sensitive to temperature. So for accuracy, wait at least 15 second between shots. It'll probably still hit pop cans at 20 feet when fired fast, but the groups will open on paper.

There seem to be 50-60 good shots per cartridge, which is about what we expect for this kind of performance. There are many lower-powered shots after that, so you need to be mindful of stopping before you jam the gun.

Remember what I said about not tightening the cartridge too much when you pierce it. I think that will prevent the leaks some shooters report after owning the gun for a while.

How a spring-piston airgun works

noreply@blogger.com (B.B. Pelletier) — Tue, 16 Dec 2008 11:30:00 +0000

by B.B. Pelletier

Today I'm writing an emergency blog I shoehorned into the list. Sparkie, who assures me he is NOT Clark W. Griswold Jr. (Chevy Chase's Christmas Vacation), sent me a comment with his interpretation of how a spring-piston airgun worked. He was off a little, as many people are, so today I will show you exactly how a spring-piston gun works.

The spring-piston airgun is the simplest type of powerplant from the standpoint of parts. There are but a few. It's a wonder that it's also one of the most recently developed, but read this report to see the history.

The gun works by the force of a piston compressing the air in front of it to power a pellet. A powerful spring or charge of compressed gas drives the piston when the gun fires. Besides a spring, in the past both dynamite and gunpowder have been used to power the piston. On the back page of the January 2009 edition of Popular mechanics, there's a brief piece about a gas-powered gun NASA uses to test micrometeor impacts. That gun is powered by gunpowder that compresses hydrogen gas to 100,000 psi. That gun has no piston, so the sabotted projectile acts as the piston instead. Interesting!

No matter what type of spring-piston mechanism it is (breakbarrel, underlever or sidelever), the barrel aligns with an air transfer port like this when the gun fires. The air transfer port is shown at the right of the picture. These parts are in front of (to the left of) the compression tube shown below.

They all work the same
All spring-piston guns have a spring-powered piston (some have more than one) inside a compression chamber. That chamber connects to the barrel through an air transfer port. When the gun is cocked, the piston is withdrawn into the compression chamber, and air is drawn through the transfer port.

Inside the compression tube, the piston rests against the front of the compression chamber until the gun is cocked.

Here's the secret!
This is what confuses a lot of people. Inside the compression tube, which is also called the spring tube, the piston rests at the end of the tube until the gun is cocked. The air transfer port is at the end of the compression tube and leads directly to the barrel. There's no valve of any kind in this system. It's like a soda straw that you can blow through to expel a paper ball. No valve is required.

When the piston's withdrawn, it pulls air into a chamber that forms in front of it. That chamber is called the compression chamber. There's nothing mechanical between the piston and the barrel, where the pellet sits.

When the piston is withdrawn upon cocking, a compression chamber forms in front of it. After that chamber lies the air transfer port and after that is the barrel.

When you load a pellet into the barrel, it forms an airtight seal. When the barrel is plugged with a pellet, the piston goes forward and compresses the air in front of it and the air presses hard on the pellet until it overcomes the pellet's resistance. The pressure of the compressed air is high--above 1,200 psi in tests that have been done. But the AMOUNT of air at that pressure is very small--just what was in the compression chamber.

So, the pellet gets swatted on its tail by a tiny puff of air at very high pressure. The pellet cannot remain where it is, so it starts moving down the barrel. As it does, the air behind it loses pressure rapidly. After 8-10 inches, the air is almost at the same pressure as it is outside the gun. The pellet has accelerated to as fast as it will go by this point.

That's all there is to it
There's nothing more than that at work in a spring-piston airgun. There are different designs of powerplants, of course, but they all work by the same simple design. In a Whiscombe rifle, two pistons that are opposed come together like the clapping of hands, with the air transfer port at the center of where they meet. But the operation of the piston(s) doesn't change.

Back in the 1960s, Jack Lewis, a noted gun writer and editor, saw a cross-section drawing of a spring-piston rifle and assumed that the blank space occupied by the air transfer port was a reed valve. He proceeded to describe the operation of that valve in great detail in his article about how a certain spring gun worked. The only problem was that THERE WAS NO VALVE!

What I am showing you here is all there is to this design.

Sparkie and anyone else who wants to learn more about how spring-piston guns work--here are two recommended posts. Both are multi-part reports.

The air transfer port

Spring gun tune

2008 Long-range Airgun Silhouette Shooters Organization shootLASSO

noreply@blogger.com (B.B. Pelletier) — Mon, 15 Dec 2008 11:30:00 +0000

by B.B. Pelletier

Last Saturday, I attended the 2008 LASSO shoot on the Boyd Farm in Lavon, Texas. They have 1,000 acres of grazing land and generously allow Eric Henderson to host the shoot on one of the lower pastures. This shoot is for big bore airguns.

The targets are half-sized steel silhouettes of rams placed roughly at 100, 150, 200, 250 and 300 yards. This year I believe they ranged between 107 and 300 yards because several shooters measured them with laser rangefinders. The two closest targets that were 107 and 170 yards have round steel plates that fall out when hit. A shooter can aim to knock these plates out of the target and get extra points.

Before the shoot, Dennis Quackenbush (dark blue on the top right) makes several announcements to the shooters.

The winds was ferocious! Gusts were hitting 40 m.p.h. and the average wind from 9 o'clock was 20 m.p.h. While those big bullets weigh more than smallbore pellets, they can't buck that kind of wind out to 300 yards, so allowances had to be made.

Speaking of smallbores, some local shooters showed up with some smallbore PCPs and set up a range of their own off to the side. They were there to see what the big bores were all about, but they had some impressive guns of their own--including a BSA Super 10 that was so quiet all I heard was the hammer dropping. It shot 10.5-grain Premiers at 940 f.p.s. and could hold a reasonable group out to 50 yards despite the wind.

Wayne--here's a guy who shoots like you. No recliner, though.

Every year I try to notice the theme of the shoot, and this year it was advancement. Instead of just buying guns and shooting them, I saw shooters who were taking the technology into their own hands and developing things not seen before. One of these was a sidelever that took only a few ounces of effort to open and close. It was so smooth that it used a magnet to hold the handle in the closed position to prevent it from opening under its own weight.

This clever sidelever needs almost no effort to open.

One pair of shooting buddies arrived with all the creature comforts, including an ATV to ferry them around the grounds. There was a rack for rifles built into the bed, and it was clear these guys took their hobby most seriously.

These guys know how to live!

Another shooter had a Buntline pistol that got two shots at an identical 660 f.p.s. That's pretty fast when you consider he's shooting a 500-grain slug! An air pistol that generates 484 foot-pounds of energy at the muzzle is a big deal! I will show it shooting in the video I'm compiling.

David enjoys his .308 pistol so much that he bought a companion at the LASSO meet. He shoots with open sights.

Other shooters had variations of Quackenbush big bores they had taken to new heights. There weren't as many Korean guns there this year, but several key shooters who normally use them failed to attend for various reasons.

This man sights-in his new Quackenbush .50 ball shooter after purchasing it from another shooter at LASSO.

LASSO host Eric Hernderson gets into a prone position to shoot his Quackenbush .308.

You can't shoot these guns without air. Since they get 2 to 4 shots per fill, that means a LOT of air. Eric had his compressor, and everyone was filling their carbon fiber tanks throughout the match. A typical rifle may get 40-60 shots per tank, so a compressor is a good thing to have. Eric's unit was busy most of the time filling many carbon-fiber tanks to 4500 psi.

Eric's compressor supplied all the air the shooters needed.

As the day progressed, the wind increased in force to the point that the competitors had something major to contend with come contest time. I had to leave before the match was finished, unfortunately, because my kidney stones were acting up. But there will be a LASSO again next year and several airgun shows before it to acquire that big bore. Is 2009 the year you want to get in on the fun?

I'll also be writing an article and making a video soon, so this isn't the last you have seen of this event.

How I learned to love guns

noreply@blogger.com (B.B. Pelletier) — Fri, 12 Dec 2008 11:30:00 +0000

Before I turn today's blog over to my wife, I have an announcement. Tomorrow the LASSO big bore airgun shoot will be held outside Dallas, Texas. I will be there to photograph things for you and also to conduct an experiment. Dennis Quackenbush dreamed this one up after reading all the conjecture about maximum velocities on the forums. He has constructed a testbed airgun that will shoot super-lightweight projectiles in an attempt to set the speed record for a PCP airgun. His gun has barrels in .25 and .375 caliber, so we will see the results of two different guns. They're smoothbores, of course, because velocity is the only thing we're testing.

I will report the results next week.

If you live near Dallas and want to see what big bore airguns are all about, visit this website:

LASSO '08

Now, on to today's blog.

How I learned to love guns

by Edith "Mrs. B.B." Gaylord

March 23, 1983, we moved into the first house we ever owned. We'd been living in my apartment after getting married the previous May. We each brought something to the marriage...I brought 8 house cats, Tom brought guns.

A couple days after we moved in, the previous homeowner stopped by with a housewarming gift and some chit-chat. As she walked out the door, she said, "Oh, yes, you've got mice." Nice parting words! Actually, I didn't have any fear of rodents, plus I was quite certain our cats could take care of them. Although they were house-bound cats, their hunting instincts were still intact. Well, sort of.

If you know anything about cats, you know they enjoy playing with their food. And, if the food's alive, even better! I clearly remember the first time our cat Dizzy brought the first live mouse up from the basement. The minute he put the mouse on the floor, the other 7 cats gathered around and formed a circle...what I call a "coven of cats." Tom quickly grabbed the Sheridan Blue Streak, loaded and pumped it, and yelled for me to move the cats out of the way so he wouldn't shoot them. Tom finally got a clear shot and quickly dispatched the mouse.

I soon realized that Tom wouldn't always be home to eliminate rodents, so I asked him to show me how to shoot the Sheridan. After several training sessions, I was ready for bear...I mean mice. We hung a yellow twist tie off the gun's triggerguard so I could distinguish it from the other rifles. Plus, that reminded me to grab the yellow plastic box of pellets, which were the most accurate. Over the years, I used our trusty Blue Streak to dispatch a number of mice, one snake outside the basement door and several rats that had moved into the planter outside the front door.

In time, I learned more about firearms and airguns (and even airsoft guns). The only reason I was able to enjoy guns was due to Tom's non-threatening, non-macho way of introducing them to me. He wasn't trying to impress me with anything. If they're in the house, whether they're airguns or firearms, I should know how they work, how to use them, how to load them and what type of ammo they use.

Fast forward 25+ years, and we now have our concealed carry permits. While I know how to shoot all the airguns, I don't know how to load and shoot all the firearms because I haven't had the time to go to the outdoor range. However, I DO know how to load and shoot all the self-defense guns. And I'm not afraid to use them. Every couple of weeks, we go to an indoor range and shoot our .45 autos. It's the caliber of my carry gun, and I love it!

Tom has done such a good job of teaching me about guns, that I now encourage him to buy almost any gun he wants. Recently, I suggested that he buy another gun. Know what he said? "I think I have enough for right now. Maybe next year."

Don't you wish your wife encouraged you to buy guns? If you introduce her to guns with the right attitude and the right guns, she just might!

Comparing regulated and unregulated airguns

noreply@blogger.com (B.B. Pelletier) — Thu, 11 Dec 2008 11:30:00 +0000

by B.B. Pelletier

Mr. B. requested this one--comparing regulated precharged pneumatics to unregulated PCPs.

What is a regulator?
First, what is a regulator and how does it work? A firing valve in a PCP does not operate at its peak at 3,000 psi--not even close. Most of them work best down around 2,000 psi and some work best at even lower pressure. But, the fact is that they still do work acceptably well at higher pressure. So, the gun gives a string of shots at a more or less constant velocity until it drops below the lowest pressure at which the valve functions well.

Valve lock
Just above the top-end operating pressure, the valve starts closing sooner than it should. When a certain pressure is exceeded, the gun begins to shoot slower than it's capable of shooting. It continues to do this until the internal pressure drops below the point where valve lock starts happening.

An air valve has a range of pressure--from low to high. As long as the air that's supplied to it stays within that range, the gun shoots at a constant velocity, more or less. And it's the "more or less" that's of great concern to airgunners.

An unregulated gun
I have a Daystate Harrier that operates best between 2650 psi and 2,000 psi. In that range, I get 24 shots of 10.6-grain Beeman Kodiaks going about 920 f.p.s. They will not vary more than 20 f.p.s. throughout the entire range. But fill to 2700 psi, and the pellet might go only 880 f.p.s. for the first two or three shots. Continue shooting after the 24 good shots (pressure falling below 2000 psi), and the velocity drops again into the 800s.

That is what a fairly good unregulated gun will do. I've seen better ones that would keep their strings within 10 f.p.s. throughout the range. All valves are not of equal quality and stability. I've also seen valves that varied more throughout their range. The AirForce Talon SS will often vary by 30 f.p.s. throughout its range, yet still shoots half-inch 5-shot groups at 50 yards.

A regulated gun
What about a regulated gun? Well, a regulator lowers the pressure of the reservoir to an ideal level before making it available to the valve. You might want to read my report on the air pressure regulator. If I installed a regulator in the reservoir of my Harrier, I could probably drop the velocity variation within the string of shots from 20 f.p.s. down to 10 f.p.s. or, perhaps, even less. I've tested PCP guns that varied by only two f.p.s. throughout their entire string of usable shots.

However, by installing a pressure regulator with its firing chamber inside the reservoir of my Harrier, I'd be subtracting volume from the reservoir. In other words, less room for air. That could be offset by increasing the pressure in the reservoir, but there's a point beyond which the regulator will not operate. So you can't just keep increasing the pressure indefinitely.

What are the benefits?
How would I benefit if I installed a reg in the Harrier? Well, quite probably I would pick up a shot or two. Experience shows that with small reservoirs, like the one in the Harrier, a reg will add only a shot or two to the total string. And all the shots would be closer in velocity because the firing valve would be working at the ideal pressure. The question I have to answer is if I think it's worth a couple extra shots and a slightly tighter velocity variation to go to the trouble of installing a regulator.

I decided that it wasn't, because my Harrier operates at a nice low max pressure. It's easy to pump to 2650 psi; much easier than to pump to 3,000 psi. At least, it is for me.

On the other hand, my Career 707 went from 30 usable shots to over 60 at the same power with a regulator. And the velocity variation of those shots dropped from over 30 f.p.s. to around 10 f.p.s. In that case, it was definitely worth the effort to install the reg.

Some things to consider
Some guns aren't suited for regulators. The AirForce guns, for example, cannot be easily regulated because of how their tanks are made. Any regulator would have to be external to the tank, which would add to the rifle's length of pull. The Benjamin Discovery has a small reservoir like the Harrier, so adding a regulator might not gain an advantage in total shots, but it might tighten the extreme spread of the string, which is on the order of 30-35 f.p.s. right now.

The final thing I want to say about regulators is they will all fail at some point. That's a fact that cannot be denied. I'm not talking about decades of time, either. Regs are not known for lasting a long time. The greater the pressure differential (difference between reservoir pressure and firing pressure) they must deal with, the shorter their life tends to be. When they go, you usually end up with an unregulated gun. In some cases, you have a broken gun that has to be repaired to work at all.

The USFT
For that reason, Larry Durham decided not to regulate the design of what became the USFT rifle. He felt it's better to have an easily repairable rifle than to have a super-tight velocity spread. The USFT won the 2007 Field Target World Championship.

Here are my personal feelings. I like regulators on 10-meter guns, where they seem to last a long time. But on a sporting airgun, I like an unregulated but balanced valve that I know will outlast any regulator. However, when the reg is working, it makes for a wonderful airgun experience. I cannot deny that.